Various tweaks

Fixed a minor bug in GenerateLineList that would cause a blank line
to disappear under certain circumstances.  Harmless, but odd.

Added a width property to DefSymbol.

Updated comments.

SourceGen/AsmGen/AsmMerlin32.cs

@@ -388,7 +388,7 @@ namespace SourceGen.AsmGen {
 
         // IGenerator
         public void OutputAsmConfig() {
-            // nothing to do
+            // nothing to do (though we could emit "xc off" for 6502)
         }
 
         // IGenerator

SourceGen/DataAnalysis.cs

@@ -150,6 +150,8 @@ namespace SourceGen {
                         // Either way there's nothing further for us to do.  (Technically we
                         // would want to treat it like the no-descriptor case if the type was
                         // numeric/Address, but we don't allow that for instructions.)
+                        //
+                        // Project and platform symbols are applied later.
                         Debug.Assert(attr.DataDescriptor.FormatSubType !=
                             FormatDescriptor.SubType.Address);
                         continue;

SourceGen/DefSymbol.cs

@@ -14,13 +14,12 @@
  * limitations under the License.
  */
 using System;
-using System.Collections.Generic;
 using System.Diagnostics;
 
 namespace SourceGen {
     /// <summary>
     /// Subclass of Symbol used for symbols defined in the platform or project.
-    /// 
+    ///
     /// Instances are immutable.
     /// </summary>
     public class DefSymbol : Symbol {
@@ -34,8 +33,18 @@ namespace SourceGen {
         /// </summary>
         public string Comment { get; private set; }
 
+        /// <summary>
+        /// Platform symbols only: tag used to organize symbols into groups.  Used by
+        /// extension scripts.
+        /// </summary>
         public string Tag { get; private set; }
 
+        /// <summary>
+        /// Number of bytes referenced by the symbol.  Useful for identifying two-byte and
+        /// three-byte pointers.  Used for Variables.
+        /// </summary>
+        public int Width { get; private set; }
+
         /// <summary>
         /// Cross-reference data, generated by the analyzer.
         /// </summary>

SourceGen/LineListGen.cs

@@ -713,6 +713,7 @@ namespace SourceGen {
             // Create temporary list to hold new lines.  Set the initial capacity to
             // the previous size, on the assumption that it won't change much.
             List<Line> newLines = new List<Line>(endIndex - startIndex + 1);
+
             GenerateLineList(startOffset, endOffset, newLines);
 
             // Out with the old, in with the new.
@@ -904,6 +905,7 @@ namespace SourceGen {
                     addBlank = true;
                 }
             }
+
             int offset = startOffset;
             while (offset <= endOffset) {
                 Anattrib attr = mProject.GetAnattrib(offset);
@@ -1034,10 +1036,10 @@ namespace SourceGen {
                 }
             }
 
-            // See if there were any address shifts in this section.  If so, insert an ORG
-            // statement as the first entry for the offset.  We're expecting to have very
-            // few AddressMap entries (usually just one), so it's more efficient to process
-            // them here and walk through the sub-list than it is to ping the address map
+            // See if there were any address shifts in this section.  If so, go back and
+            // insert an ORG statement as the first entry for the offset.  We're expecting to
+            // have very few AddressMap entries (usually just one), so it's more efficient to
+            // process them here and walk through the sub-list than it is to ping the address map
             // at every line.
             //
             // It should not be possible for an address map change to appear in the middle
@@ -1067,8 +1069,17 @@ namespace SourceGen {
                 // isn't the ORG at the start of the file.  (This may temporarily do
                 // double-spacing if we do a partial update, because we won't be able to
                 // "see" the previous line.  Harmless.)
-                if (ent.Offset != 0 && index > 0 && lines[index-1].LineType != Line.Type.Blank) {
-                    Line blankLine = new Line(topLine.FileOffset, 0, Line.Type.Blank);
+                //
+                // Interesting case:
+                //   .dd2 $1000
+                //   <blank>
+                //   .org $1234
+                //   .dd2 $aabb    ;comment
+                // We need to include "index == 0" or we'll lose the blank when the comment
+                // is edited.
+                if (ent.Offset != 0 &&
+                        (index == 0 || (index > 0 && lines[index-1].LineType != Line.Type.Blank))){
+                    Line blankLine = GenerateBlankLine(topLine.FileOffset);
                     lines.Insert(index, blankLine);
                 }
             }

SourceGen/WpfGui/EditDefSymbol.xaml.cs

@@ -127,7 +127,6 @@ namespace SourceGen.WpfGui {
             valueNotesLabel.Foreground = valueValid ? mDefaultLabelColor : Brushes.Red;
 
             IsValid = labelValid && labelUnique && valueValid;
-            Debug.WriteLine("VALID IS " + IsValid);
         }
 
         private bool ParseValue(out int value, out int numBase) {